1. Field of the Invention
This invention relates to the field of filtration devices for pools. More specifically, the present invention comprises a pool filter having an integrated air injection device configured to inject air into the pool filter causing a swirling motion during the backwash cycle.
2. Description of the Related Art
In most private swimming pools a water pump is used to re-circulate water from the pool through a filter and back to the pool. In most applications, a pressure-fed filter is typically placed in line immediately after the water pump. These filters typically contain filter media such as graded sand or diatomaceous earth. The filter media traps contaminants such as dirt and debris as small as 20 to 40 microns.
FIG. 1 is illustrative of a common sand filter used for a private swimming pool. In normal operating mode, water is pumped from the pool into interior 12 of filter container 10 through normal inlet 16. The water then passes through sand 14 where particulates are trapped and separated from the water. The water passes through intake inlets 40 in laterals 24 and pressure pushes the water through conduit 22 and out normal outlet 20 to recirculate the water back to the pool.
Over time, contaminants collected in sand 14 restrict water flow through sand 14 causing back pressure on the water pump. Thus, pool filtration systems should be “backwashed” routinely to remove the collected contaminants. FIG. 2 illustrates the normal process for backwashing a common sand filter. Water is pumped into filter through normal outlet 20. The water passes through the intake inlets 40 in laterals 24 and through sand 14 toward the top of filter container 10 where it exits through normal inlet 16.
During normal operation of sand filters, channels will form in sand 14 as the passing water finds and exploits paths of least resistance in sand 14. This channeling effect reduces the effectiveness of the filter as the channels enlarge, since contaminants passing through the channels are not collected by the filter. Furthermore, organic materials, calcium and other mineral deposits form within the filter media over time creating “clumps” of filter media which are substantially impermeable to water. When the filter is backwashed, water passes back through the channels and leaves most of the mineral deposits undisturbed. As such, backwashing is currently of limited effectiveness.
It would therefore be desirable to provide an improved filter which is capable of breaking up and separating mineral deposits from the filter media. It would be further desirable to provide an improved filter that is capable of disrupting the structure of the filter media to eliminate channels formed therein.